Comparison of power-free-chop and phaco-chop techniques for moderate nuclei

BACKGROUND: To compare the intraoperative and postoperative effects of power-free-chop and phaco-chop techniques for moderate nuclei in phacoemulsification surgery. METHODS: Sixty patients were evaluated in 2 groups. The power-free-chop technique was performed in Group 1 (30 eyes), and the phaco-chop technique was performed in Group 2 (30 eyes). There were no significant differences between these 2 groups. The cumulative dissipated energy (CDE), time to achieve maximum vision, corneal thickness variation, and time to return to the preoperative values were collected. All parameters were statistically compared in these 2 groups by using the chi-square test and the independent-sample t-test. RESULTS: The CDE was 5.53 ± 1.92 J in Group 1 and 7.02 ± 1.77 J in Group 2. After the operation, the mean time to recover to the maximum vision was 2.80 ± 1.42 days in Group 1 and 3.80 ± 1.92 days in Group 2. The mean postoperative corneal thickness increased 36.9 ± 14.74 μm in Group 1 and 46.20 ± 20.67 μm in Group 2. The mean time to return to preoperative pachymetry values was 3.73 ± 1.70 days and 4.83 ± 2.11 days in Group 1 and Group 2, respectively. There were significant differences in these parameters between the groups. CONCLUSIONS: The power-free-chop technique had fewer negative effects on the corneal endothelium, as less ultrasound power was used for moderate nucleus cases. This can accelerate the functional healing process and the return to preoperative physiologic values.